@adan_eslavo , Hinin provided me with this info, hopefully it can be of use:
"It depends on the dlc in which the NWonders were added.
All the gr2 and fxsxml files (respectively : 3d model and animations ; asset attribution text) are present in Sid Meier's Civilization V / Resource / Common :
- FeatureModels.fpk for the base game NW (Barringer Crater, Great Mesa, Great Reef, Krakatoa, Mt. Fuji, Old Faithful, Rock of Gibraltar)
- Upgrade1Models.fpk for the small DLC NWs (El Dorado, Fountain of Youth, Cerro de Potosi)
- Expansion2Models.fpk for G&K and BNW NWs (Mt Kailash, Mt. Sinai, Sri Pada, Uluru, King Solomon's Mines, Lake Victoria, Mt. Kilimanjaro)
As for the dds files (2d pictures applied on the 3d models), they are in Resource / DX9 :
- Upgrade1Textures.fpk for the small DLC NWs (El Dorado, Fountain of Youth, Cerro de Potosi) + SpainIsabellaTextures.fpk (for a part of the Cerro de Potosi)
- Expansion1BuildingsTextures.fpk + Expansion2BuildingsTextures.fpk for the G&K and BNW DLC NW : Kilimanjaro / Lake Victoria / Mt Sinai / Solomon Mines / Sri Pada / Uluru / Mt Kailash (don't know why there are present in those two files, maybe there is a difference, but I can't see it at first glance)
- For the base game NW, can't find them yet."